They’re sold with promises to do things like “rest your digestive system,” “rejuvenate your body,” “increase energy,” and “eliminate toxins.” Consumer Reports did not see a lot of evidence to back some of the claims the manufacturers make. None promise you’ll drop pounds, but Consumer Reports says that you probably will in the short term because most are relatively low in calories.

Consumer Reports reached out to manufacturers regarding the claims they make. Some did not respond. Those that did defended the benefits of their products. After reviewing the information and conducting their own research, Consumer Reports’ health experts remain unconvinced that the products are worth the money.

The juices Consumer Reports reviewed also tend to be too low in fiber and protein, and too high in sugars. And they’re pricey; three days of juices can cost as much as $200.

If you’re healthy and you do a cleanse for one, two, or even three days, Consumer Reports says that it’s probably not harmful. But any longer than that really isn’t smart because they don’t contain all of the nutrients your body needs.

For truly sustainable changes, Consumer Reports reminds us that healthy eating is a better way to go. As with any diet, Consumer Reports advises checking with your doctor first if you want to do a cleanse.